NASA lifts off with closed loop project for space waste

Space detris could be recycled and made into radiation shields for spacecraft exploration if research from NASA scientists bears fruit.

The discs produced by heating and compressing a sample of trash simulants. Credit: NASA

The high amount of plastics waste packaging generated by spacecraft missions is thought to be ideal material to make such shields from according to researchers at the Kennedy Space Center in Florida, US.

They are currently evaluating small tiles made of space trash to find out whether they can be stored aboard spacecraft safely, or used for radiation shielding during a deep-space mission.

The circular tiles were produced at NASA's Ames Research Center in California, where engineers have developed and built a compactor that melts waste materials, but doesn't incinerate them.

Instead, the compacter produces eight-inch diameter tiles about half an inch thick from items such as plastic water bottles, clothing scraps, duct tape and foil drink pouches. These are effectively patched together in a single tile along with an amalgam of other materials left from a day of living in space.

According to Mary Hummerick, a Qinetiq North America microbiologist working on the project, one of the ways these discs could be reused is as a radiation shield.

"The idea is to make these tiles, and, if the plastic components are high enough, they could actually shield radiation," she said.

Possible areas for increased radiation shielding include astronauts' sleeping quarters or perhaps a small area in the spacecraft that would be built up to serve as a storm shelter to protect crews from solar flare effects.

Hummerick and her team are trying to identify if the tiles, which are made according to recipes based on waste from shuttle missions, free of microorganisms and safe enough for astronauts to come into contact with daily.

"They are achieving sterilization for the most part," Hummerick revealed. "What we don't know is, can a few possible surviving bacteria go inert and then grow back?"

Handling waste materials is an important consideration for NASA mission planners and astronauts for several reasons due to limited resources and storage space on spacecraft.

Crews are not allowed to jettison their rubbish as they travel through space as it could land on, and possibly contaminate, a planet or moon.

Another aim of the project is to remove water from the waste so it can be reused by the crew. Because water is so dense, it is very heavy to take into space, so processing it for reuse is seen as essential to a successful mission beyond low-Earth orbit.

"The mindset is, with limited resources, whatever you can use, you want to be able to repurpose that," Hummerick explained. "Water is a very valuable commodity, so you want to recover all of that you can."